Candle composition (was Re: Looking for advice on 1 lb. bp rocket delay comps

In article <1146179205.584417.306100@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
hhc314@xxxxxxxxx says...

I couldn't find the terms Candle Comp or Candle Composition even
indexed in the modern boorks Like Hardt or Lancaster's 4th edition, but
it is well described in Davis on page 79 and in Weingart's second
edition on page 76 although the mixture of the composition slightly
differ. I see no obvious reason why it could not be used as a delay
composition on rockets, particularly when a trail of continuing sparks
is wanted, much as Tom C. suggests.

Kindest regards, Harry C.


See table 15-31, p. 193 of Hardt where 3 candle compositions are listed, and
discussion pp. 194-8.

Lancaster describes these compositions under the traditional English name "delay
fuse" and gives two compositions on p. 249 of the fourth ed., and on p. 250
gives another without any free sulphur.

The American practice was to include dextrine and to granulate these
compositions with water. The usual explanations are that granulated composition
passed more easily through shifting boards, was dust-free, etc. While these
things are true, one point I have not seen mentioned in print is that the custom
of at least some makers was to use the composition (charging via machines like
that illustrated on p. 82 of Weingart [1947]) while still slightly damp.

The reason proposed for this was that the composition, consolidated in this
condition, dried in storage to form a hard plug, which these makers felt was
more solid than could be made by ramming the composition dry; and that this
prevented the problem of overly rapid 'machine gun' discharge of the stars.
Chalk whiting (calcium carbonate) was often mixed in such compositions, under
the theory that it would prevent acid interaction between the chlorate stars
used in the candles and the sulphur in the composition, while it was in this
semi-damp condition and hence more prone to react. Composition 3 in Hardt's
table 15-31 cited above came from such a manfacturer. The theory noted above
seemed rather dubious to us, and it was not deemed worthy of mention in the
text. I describe it now purely for whatever value it may have as pyrotechnic
folklore.


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